Conventionally, as a battery system which includes a plurality of flat secondary batteries, there has been provided a battery system which is manufactured by taking into account vibration resistance and impact resistance (see JP 2014-44884 A, for example). Such a battery system includes: a battery assembly formed by stacking a plurality of flat secondary batteries in a thickness direction; a pair of end plates disposed on both end surfaces of the battery assembly in a stacking direction; bind bars connected to the pair of end plates and fixing the flat secondary batteries in the stacking direction by applying pressure to the flat secondary batteries; and an intermediate reinforcing plate disposed between the flat secondary batteries which form the battery assembly and fixed to the bind bars.
In such a battery system, the end plates and the intermediate reinforcing plate fix the stacked flat secondary batteries in a pressurized state. That is, in the battery system, the battery assembly (flat secondary batteries) is fixed in a state where the battery assembly is positioned with reference to the intermediate reinforcing plate.
In the above-mentioned battery system, the intermediate reinforcing plate is fixed to the bind bars and hence, the battery assembly (flat secondary batteries) is positioned in accordance with the posture of the intermediate reinforcing plate. Accordingly, when the arrangement or the posture of the intermediate reinforcing plate is inappropriate, the battery assembly (flat secondary batteries) is also positioned and fixed in an inappropriate state.